1. Field of the Invention
The present invention relates to concentrated, pumpable suspensions of water-soluble polymers, the preparation thereof and utilization of same as thickening agents for aqueous media.
2. Description of the Prior Art
Synthetic and natural organic polymers that dissolve or disperse in water and which, by dissolving or dispersing in water, display thickening or flocculating properties, are known to have widespread industrial applications in the construction, paint, paper, textile, cosmetic, and food industries, and in waste-water treatment, phytochemistry, drilling, assisted oil recovery, and the like.
In many applications, these polymers or hydrocolloids must be employed in the form of a low-concentration aqueous solution or dispersion. It is also known that the major disadvantage of most water-soluble polymer powders is that they are difficult to rapidly dissolve without using methods of high shear agitation. Under the influence of overly rapid hydration, the polymer particles swell when they come into contact with water and tend to form flocs resulting from agglomeration of the particles. These flocs are coated with a thin film, resulting in the formation of gel on the outer surfaces thereof, and same disaggregate and dissolve only with difficulty.
To facilitate dissolution of water-soluble polymers of the polyacrylamide type, there have been proposed to this art various water-in-oil emulsions that undergo phase inversion by adding water containing a surfactant thereto. However, these emulsions are not very stable and tend to separate into two phases during storage.
Solutions having varying concentrations of polymer have also been proposed to this art. Formulations of this type are disclosed in U.S. Pat. Nos. 3,763,071, 3,894,880 and 4,176,107, for example.